1. Field of the Invention
This invention relates to the field of slide mechanisms and, in particular, to friction slide mechanisms.
2. Description of the Related Art
Various available slide assemblies are used for mounting drawers and other loads to provide ease of longitudinal motion of the load in a generally horizontal plane. The primary performance criteria for slides is the amount of vertical and horizontal play, the consistency of the force and the maximum force required to operate the slide, strength and durability. The other major consideration is cost.
While some low end slides are manufactured from plastic, strength and durability requirements typically necessitate that the slide segments or rails be manufactured from metal.
There are three standard types of slide assemblies: a ball bearing slide; a roller slide; and a friction slide. A ball bearing slide utilizes slide segments or rails separated by ball bearings which are maintained in alignment by ball retainers and bridges. In most environments, the ball bearing slide provides for the smoothest travel, although at the greatest cost. The roller slide utilizes a pair of segments, each of which includes a roller and a track for receiving a roller from the mating slide segment. While not as smooth or as durable as the ball baring slide mechanism, the roller slide is less expensive than the ball bearing slide. The friction slide is the least expensive but least smooth of the slide mechanisms, and generally comprises two slide segments or rails which slide directly against one another. Undesirably, this arrangement results in jerky movement and substantial wear on the slide mechanism. While efforts have been made to overcome this drawback by spraying a carbon coating on the mating slide segments, the carbon coating tends to quickly wear off and pieces of the carbon coating tend to flake off and into the working environment of the slide. Typically, the carbon coating will have a thickness of no more than about 0.002 inches. While low-quality slides are occasionally manufactured from plastic, plastic provides insufficient strength to support all but the lightest load.
In certain working environments, such as a slide for a table saw, a very smooth and precise slide may be desired, yet a constant presence of sawdust tends to interfere with the working of the slide mechanism. Accordingly, there is a need for an improved slide mechanism which overcomes the drawbacks of the prior art, preferably at relatively low cost.